Refrigerating system



June 23, 1936.

W. G. MIDNIGHT REFRIGERATING SYSTEM Original Filed Oct. 20, 193-3 INVENTOR.

ATTORNEYS v Patented June 23, 1936 I UNITED STATES PATENT REFEIGEBATNG SYSTEM Wilbur G. Midnight, Bay Village, Ohio, asslgnor to Perfection Stove Company, Cleveland, Ohio, a corporation of Ohio Application October 20, 1933, Serial No. 694,453 Renewed January 25, 1935 14 Claims. (Cl. 62 -1205) OFFICE This invention relates t6 artificial refrigeration, and its principal object is to provide a refrigeration apparatus or system of the intermittent absorption class that includes thoroughly dependable means for returning residue liquid from the evaporator to the generator-absorber section of the system at sufficiently frequent intervals to insure against impairing the effectiveness of the evaporator by undue accumulations therein of residue liquid, and that involves an arrangement preventing the return, in any appreciable amount, by said means, of freshly distilled anhydrous refrigerant.

The invention is, in fact, an improvement on the refrigeration apparatus described and claimed in Letters Patent No. 1,816,975, dated August 4, 1931. The means set forth in said patent for returning residue liquid from the evaporator to the generator-absorber section of the system is thoroughly practical, efficient and reliable when, in the manufacture of the apparatus, due care is exercised in the accurate proportioning and arranging of the parts and, in the use thereof, operating conditions are reasonably normal. Otherwise the liquid return is liable to carry back too little or too much liquid when it functions and thus reduce the effectiveness of the evaporator; in the first instance, by allowing the evaporator to become loaded with a mixture proportionately low in refrigerant content, and in the second instance, by robbing it of a part of its charge of freshly distilled anhydrous refrigerant.

In the present invention these difficulties are eliminated by providing a construction that requires less precision in its manufacture and that operates in such manner as to positively prevent return of the freshly distilled anhydrous refrigerant by segregating and withholding it from the evaporator until the residue of the previous charge has been returned therefrom.

The principal object above set forth, with other objects hereinafter appearing, are attained in the embodiment of the invention illustrated in the accompanying drawing wherein the figure is a diagram somewhat in the nature of a sectional side elevation of a refrigerating machine incorporating my improvements.

' An understanding of the general structure and operation of the invention may be had from the following description wherein the parts of the apparatus or system are designated by reference characters.

At the conclusion of a cycle of operation all, or practically all, of the mixture of refrigerant, which may consist of ammonia, and an absorbent therefor, which may consist of water (such mixture'being known as liquor) is present in the generator-absorber i the liquid level at this time being at about that indicated by the dotted line a.

A cycle of operation is started by rendering the 6 heating means 2 effective. As herein illustrated, said heating means consists of oil burners I, having chimneys 4. The burners receive their fuel supply through a pipe 5 from a receptacle 6 over which is supported, in inverted position, a bottle- 10 like reservoir 1 that preferably holds just enough fuel to sustain a single heating period, the burners going out when the fuel is exhausted. As the liquor within the generator-absorber i boils, the vapors thereof rise through the fluid conveying means or vapor delivery conduit l0 and, passing through a dehydrator ii and condenser unit or coil i2, are discharged in liquid form into a reservoir I3. It will be noted that the outlet end of the fluid conveying means, including the parts ill go to l2, dips into a sump it that is formed in the bottom of the reservoir l3.

The dehydrator ii and condenser unit or coil i2 are herein shown as continuations of the conduit i0 and they, with the reservoir I3, are submerged in a body of cooling liquid, such as water, that is contained within a tank i5, shown as supported upon the top of a cabinet [6 having insulated walls enclosing the refrigeration compartment ll.

Enclosed within the insulated top of the cabinet IB, according to the present embodiment, is a receiver 20 having an extension 2i that de-- pends below said top wall. 22 designates the evaporator which may be in the nature of a circulating unit or coil that communicates with the space enclosed by the extension 2i. The lower end of said extension and the evaporator are preferably contained within a brine tank 23.

At the very beginning of the heating period, before the pressure within the system has reached a value sufficiently great to cause effective condensation at approximately the temperature of the cooling liquid in the tank l5, the first vapors, inconsequential in amount, will condense in the coolest part of the system which, at this time, is the evaporator; and they find their way from the outlet end of the condenser coil or unit it to the evaporator through a branch conduit 25.

As the heating-condensing period progresses, the pressure within the system rises quite rapidly and forces any residue liquid that was left in the evaporator and in the extension 2i at the conclusion of the previous cooling period, up into the receiving end of a liquid return conduit 20, which receiving end dips into the extension 2! to very near the bottom thereof. The discharge end of the liquid return conduit opens into the generator-absorber l below the liquid level therein, the same being shown herein as opening through the bottom of said vessel; and it will be observed that the high part of said conduit is well above the maximum liquid level in the receiver II, which level is indicated by the dotted line b. The liquid return conduit, therefore, is in the nature of a'siphon, and while the liquid is being forced up into the receiving end or short leg of the conduit, liquid from the generator-absorber is likewise being forced up the long leg thereof. As the columns of liquid in the two ends of the conduit approach each other, the gas that is trapped between said columns, and which is rich in refrigerant, is compressed and partially absorbed by the relatively weal: liquor of the two columns, tending to draw the columns toward each other, and this results in an almost continuous body of liquid extending throughout the length of the liquid return conduit, causing a siphonic action to be set up which draws over into the generator-absorber all of the liquid within the extension Il down to the level of the receiving end of the conduit 28.

Here it might be well to explain that in the practical working of the liquid return conduit, its operation does not not always consist of a continuous and uninterrupted carrying over of the residue liquid from the evaporator to the generator-absorber, but its operation may be more or less spasmodic, the siphonic action being interrupted one or more times by the possible vaporination of any slugs of relatively pure refrigerant that is carried over with the residue liquid.

As the heating-condensing period further advances, and under the pressure now prevailing within the system, the vapors from the generatorabsorber condense within the coil or unit I! and are delivered to the reservoir IS, in which vessel the pressure is lower than elsewhere within the,

system by reason of the fact that it is shut off therefrom by the accumulation of liquid about the discharge end of the conduit through which it receives its supply.

when the heating means 2 is rendered ineflective, as by the going out of the burners 4, the boiling of the liquor within the generator-absorber I will cease and the pressure within the system will rapidly fall. The liquid level within the generator-absorber at this time is about that indicated by the dotted line 0, and of course said liquor is relatively weak, a very high percentage of the refrigerant having been distilled over into the reservoir it. As the pressure falls, that prevailing in all other parts of the system will be inferior to that now existing within the reservoir I I and consequently the liquid from said reservoir will be forced over into the receiver 20 through the branch conduit 25, Under conditions now existing in the system there will be no danger or likelihood of any of the anhydrous refrigerant in the receiver 20 or evaporator 23 being carried over by the liquid return conduit 26 to the generator-absorber. Any tendency for such to occur would be prevented by vaporization of the highly volatile refrigerant in warmer sections of the liquid return conduit.

The period in the cycle of operation that has been initiated by the cessation of heat is known as the cooling-evaporating period and during this period the contents of the receiver-evaporator, under the influence of the temperature of the refrigeration compartment ll, evaporates, thus extracting heat from said compartment, and passes back in the form of vapor through the gas return conduit 30 to the generator-absorber i, the same being injected into the body of relatively weak liquor, by the discharge end of said conduit, for re-absorption.

The term generator-absorber is used herein in a general sense and is intended to apply to either a single vessel functioning alternately as a generator and an absorber, or to two vessels that serve, respectively, as a generator and an absorber, or any equivalent thereof. A similar construction is to be placed upon the terms receiver-evaporator" and reservoir-condenser". Such obvious modifications are deemed unnecessary of specific illustration.

Having thus described my invention, what I claim is:

l. A refrigerating system of the intermittent absorption type including a generator-absorber, areservoir for freshly distilled refrigerant, a receiver-evaporator, the latter being located at an elevation above the maximum liquid level in the generator-absorber, means establishing communication between the foregoing elements and through which a complete operative refrigeration cycle is effected and involving fluid conveying means opening into the reservoir adjacent thebottom thereof and adapted to be liquid sealed therein, said means leading to the receiver-evaporator, and a valveless liquid return conduit in-. dependent of the beforementioned communica-I tion means connecting the receiver-evaporator and the generator-absorber.

2. A refrigeratng system of the intermittent absorption type including a generator-absorber, a reservoir for freshly distilled refrigerant, a receiver-evaporator communicating with the reservoir adjacent the bottom of the latter, the receiver-evaporator being located at an elevation above the maximum liquid level in the generatorabsorber, means establishing communication between the foregoing elements and through which a complete operative refrigeration cycle is effected, and a valveless liquid return conduit independent of the beforementioned communication means connecting the receiver-evaporator and the generator-absorber.

3. A refrigerating system of the intermittent absorption type including a generator-absorber, a condenser, a reservoir for freshly distilled refrigerant, the same incorporating a sump, a receiver-evaporator located at an elevation above the maximum liquid level in the generator-absorber, means establishing communication between the foregoing elements and through which a complete operative refrigeration cycle is effected and involving fluid conveying means adapted to be liquid sealed in the aforesaid sump and through which the reservoir receives its supply of liquid from the condenser and discharges it to the receiver-evaporator, and a valveless liquid return conduit independent of the beforementioned communication means connecting the receiver-evaporator and the generator-absorber.

4. A refrigerating system including a generator-absorber, a condenser-reservoir, a receiverevaporator, vapor conveying means leading from the generator-absorber and communicating with the condenser-reservoir and the receiver-evaporator, means for returning gas from the receiverevaporator to the generator-absorber, and a liquid return conduit leading from the evaporator to the generator-absorber.

5. A refrigerating system including a generator-absorber, a condenser-reservoir, a receiver, an evaporator into which the receiver discharges, vapor conveying means leading from the generator-absorber to the condenser-reservoir and to the receiver, a conduit through which gas returns from the evaporatorv to the generator-absorber section, and a liquid return conduit leading from the evaporator to the generator-absorber section.

6. A refrigerating system including a generator-absorber section, a receiver-evaporator section, a condenser-reservoir, a trap opening into the reservoir portion of the latter, fluid conveying means establishing communication between the generator-absorber section, the condenser-reservoir and the receiver-evaporator section and being liquid sealed in said trap, a gas return conduit connecting the receiver-evaporator section and the generator-absorber section, and a liquid return conduit for transferring residue liquid from the receiver-evaporator section to the generator-absorber section.

7. A refrigerating system including a generator-absorber section, a receiver-evaporator section, a condenser, a reservoir, fluid conveying means leading from the generator-absorber section to the condenser and reservoir and to the receiver-evaporator section, a gas return conduit connecting the receiver-evaporator section and the generator-absorber section, and a liquid return conduit independent of the beforementioned fluid conveying means leading from the receiverevaporator section to the generator-absorber section.

8. A refrigerating system including a generator-absorber section, a receiver-evaporator section, a condenser-reservoir section, fluid conveying means connecting the generator-absorber section and the condenser-reservoir section, a, conduit leading from the condenser reservoir section to the receiver-evaporator section, a gas return conduit connecting the receiver-evaporator section and the generator-absorber section, and a liquid return conduit independent of said fluid conveying means leading from the receiver- :lvaporator section to the generator-absorber sec- 9. A refrigerating system including a generator-absorber section, a receiver-evaporator section, a condenser, a reservoir, fluid conveying means connecting the generator-absorber section, the condenser and the reservoir, the same being'liquld sealed in the latter element, a conduit through which communication is established between the reservoir and the receiver-evaporator section, a gas return conduit connecting the receiver-evaporator section and the generatorabsorber section, and a liquid return conduit leading from a low point in the receiver-evaporator section upwardly above the maximum liquid level therein and thence over and downwardly to the generator-absorber section and communicat ing therewith at a point below the maximum liquid level in the latter section.

10. A refrigerating system including a generator-absorber section, a receiver-evaporator section, a condenser, a reservoir, fluid delivery means leading from the generator-absorber section to the condenser and from the condenser through separate branches to the reservoir and to the receiver-evaporator section, a gas return conduit connecting the receiver-evaporator section and the generator-absorber section, and a. liquid return conduit leading from a low point in the receiver-evaporator section upwardly above the maximum liquid level therein and thence over and downwardly and opening into the generatorabsorber section at a point below the maximum liquid level in the latter section.

11. A refrigerating system including a generator-absorber, a condenser-reservoir, a receiver, an evaporator below and communicatively connected with the receiver and into which liquid gravitates from the receiver, fluid conveying means connecting the generator-absorber and the condenser-reservoir, a branch conduit leading from said conveying means in advance of the reservoir and opening into the receiver, a conduit through which gas returns from the evaporator to the generator-absorber, and a liquid return conduit leading from a low point in the evaporator upwardly above the maximum liquid level in the receiver and thence over and downwardly and opening into the generator-absorber at a point below the maximum liquid level therein.

12. A refrigerating system including a generator-absorber, a receiver-evaporator, a condenser-reservoir, a container for a cooling medium, fluid conveying means through which communication is established between the generator-absorber, the condenser-reservoir and the receiver-evaporator, said condenser-reservoir being located within the aforesaid container. a gas return conduit connecting the receiver-evaporator and the generator-absorber, and a liquid return conduit leading from the receiver-evaporator to the generator-absorber.

13. A refrigerating system including a generator-absorber, a receiver-evaporator, a condenser-reservoir, a container for a cooling medium,

vapor delivery means leading from the generator-absorber to the condenser-reservoir and having a part constituting a dehydrator, said dehydrator and the condenser-reservoir being located within the aforesaid container, a conduit through which the condenser-reservoir communicates with the receiver-evaporator, a gas return conduit connecting the receiver-evaporator and the generator-absorber, and a liquid return conduit leading from the receiver-evaporator to the generator-absorber.

14. A refrigerating system including a generator-absorber section, means for periodically administering heat thereto, the intervals between heating periods being known as cooling periods; a condenser, two intercommunicating vessels, one of which is arranged to receive freshly condensed refrigerant directly from the condenser during a heating period, and the second of which is adapted to have said refrigerant transferred to it by changes of pessure in the system at the 

